The present invention relates generally to ultrasonic imaging systems, and more particularly, to ultrasound lucent apparatus for use with such imaging systems.
Intravascular imaging of blood vessels and surrounding tissues continues to be of great benefit in a wide range of medical fields. In some configurations, a flexible guidewire is inserted into a patient, for example, through the femoral artery, and positioned at a desired location within the patient. An imaging catheter is then inserted into the patient and positioned at the desired location within the patient. In some embodiments, the imaging catheter is disposed in a sheath having an opening or hole at the distal end and an opening or hole in the sheath wall a number of inches from the distal tip. The imaging catheter is then guided xe2x80x9cover the wirexe2x80x9d and positioned at the desired location.
For the above-described embodiment as well as other medical procedures, including less invasive surgical procedures (LISA), it is desirable to precisely locate the guidewire distal tip or guidewire body. Locating the distal tip, for example, typically is not a trivial exercise in light of the small dimensions and generally cylindrical shape of the guidewire. For example, ultrasound imaging techniques used from outside the patient""s body may have difficulty in locating a diminutive, round guidewire. It is preferable to provide a guidewire for use with imaging systems that provide for greater ease of location and recognition. However, increasing the size of the guidewire is not desirable, particularly in light of the narrow and tortuous vasculature of the patients in many locations being treated.
The present invention provides exemplary ultrasound lucent apparatus and methods for use in a wide range of imaging and surgical procedures. At least part of the present invention is directed to providing a guidewire having a greater reflectivity to increase the likelihood the guidewire will be located and correctly positioned. In one exemplary embodiment of the present invention, an apparatus to aid ultrasound imaging or treatment of a patient comprises an elongate wire body having an outer surface and a longitudinal axis. The wire body includes a plurality of corner reflectors disposed on an embossed portion of the outer surface. The wire body is adapted to be inserted into a body lumen or a patient vasculature. In this manner, use of corner reflector technology enhances the ultrasound reflective nature to increase the acoustical reflectivity of the wire body.
In one aspect of the present invention, the embossed portion is positioned to be generally coaxial with the longitudinal axis and extends around a portion of the circumference of the wire body. Alternatively, the embossed portion includes a band around the entire circumference of the wire body.
To facilitate introduction into a patient, the wire body preferably has a diameter that is less than about 20 French. The wire body comprises a stainless steel, or tungsten in two alternative embodiments.
In one aspect, the plurality of corner reflectors each comprise first, second and third sides, with each side having a generally triangular shape and positioned to be generally orthogonal to the other two sides, such as an inside corner of a box. In one aspect, each of the three sides have an isosceles triangle shape. Alternatively, each of the three sides have a right triangle shape and share a common vertex.
In one particular aspect, the apparatus further includes a sleeve with the wire body disposed therein. Preferably, the sleeve comprises a material selected from a group of materials consisting of a plastic, a metalized plastic, a metal, a plastic-coated metal, two or more plastics of different density, and the like. In this manner, the sleeve facilitates smooth introduction of the apparatus into a patient and comprises material permissible for use within the patient.
In one aspect, the apparatus further includes a second embossed portion of the wire body, having a second plurality of corner reflectors. In another aspect, the wire body is a wound wire body. The wire body comprises a plurality of windings around the body longitudinal axis.
In one particular aspect, an ultrasound lucent wire is provided having a wound wire body. The wire body has a flexible distal end, a proximal end, a longitudinal axis. and an outer surface. The wire body includes a plurality of corner reflectors embossed in the outer surface to define an embossed portion thereof. The wire body has a diameter that is less than about 20 French.
In another embodiment, an apparatus to aid ultrasound imaging or treatment of a patient includes a hollow sleeve having an inner surface and an outer surface and a flexible wire disposed in the sleeve. At least a portion of the wire is embossed with a plurality of corner reflectors to enhance ultrasound visibility of the apparatus.
In one particular embodiment, an apparatus to aid ultrasound imaging or treatment of a patient includes a hollow sleeve having inner and outer surfaces, and a flexible wire disposed in the sleeve. The sleeve has a first portion embossed with a plurality of corner reflectors. In this manner, the corner reflectors for increasing ultrasound visibility of the apparatus are disposed on or in the sleeve.
In one aspect, the first sleeve portion embossed with the plurality of corner reflectors includes a portion of the inner surface of the sleeve. Alternatively, the corner reflectors are disposed on a portion of the outer surface of the sleeve. In one aspect, the sleeve includes a sleeve material having a sleeve material density. The first sleeve portion embossed with the corner reflectors is coated with a material having a greater density than the sleeve material density.
In one aspect, the sleeve, or the wire body, or both, includes a second embossed portion having corner reflectors. In still another aspect, the sleeve is disposed within a second sleeve.
The present invention further provides exemplary methods of performing an invasive medical procedure, such as an imaging or surgical procedure. In one method, a guide wire is provided having a wire body with a plurality of corner reflectors embossed in the guidewire body outer surface. The method includes inserting the guidewire into a patient, and positioning the guidewire at a desired location within the patient. The method includes energizing a transducer to project an ultrasound signal in the general direction of the embossed portion, and capturing a reflected signal from the embossed portion. The method includes rotating the guide wire so that the embossed portion faces away from the transducer to reduce the reflected signal. In one aspect, an ultrasound imaging catheter having the transducer also is inserted into the patient.
Other features and advantages of the invention will appear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawings.